Electrochemical means for protecting the interior of pipes against corrosion



March l2, 1929.

R. VAN A. MILLS 1,705,197 ELECTROCHEMICAL MEANS FOR PROTECTING THE INTERIOR OF PIPES AGAINST CORROSION Filed Dec. 5, 1924- 'lill/Illia THM SWG: nu,

Patented Mar. 12, 1929.

UNITED STATES PATENT OFFICE.

RONALD VAN AUEN MILLS, OF SANDY SPRING, MARYLAND, ASSIGNOR TO PETER Q. NYCE, OF WASHINGTON, DISTRICT OF COLUMBIA.

ELECTROCHEMIOAL MEANS FOR PROTECTING THE INTERIOR OF PIPES AGAINST CORROSION.

Application filed December 5, 1924. Serial No. 754,186.

The inventionrelates to an electro-chemical method of and means for protecting the interior of pipes and the like against corro sion.

lt is well known that corrosion is essentially an electro-chemical process, largely dependent upon galvanic action, and that corrosion occurs on electro-positive surfaces, that is to say, on the surfaces ilrom which an electric current leaves a metal and passes into an electrolyte. In the case of the Ordinar y pipe line, the electrolyte is the liquid which -flows through it, and which frequently contains salts of a very corrosive nature.

By providing an electro-positive material that will corrode in preference to the iron or other metal of which the pipingis composed, corrosion of the equipment is prevented.

T he inventor recognizes that the protection of iron or steel piping against corrosion by the use of an electro-positive metal in a galvanic circuit with the iron or steel to be protected is not broadly new. For example, the well known art of galvanizing iron operates on the general principles involved in the protcction of iron or steel by means of a metal that is electro-positive with respect to the iron or steel.

The disadvantages of galvanizing iron and steel as a method of protection against corrosion are (1) The thinness of the protective coating of zinc. The protection lasts only so long as the Zinc remains intact. Under the action oit corrosive fluids the zinc corrodes away and is dissolved and removed from the iron leaving the latter unprotected. (2) The thin coating of Zinc on galvanized iron is easily scratched or otherwise removed, thus exposing the iron. rlhis permits the formation of a galvanic couple between the iron and Zinc and stimulates the rapid consumption of the Zinc.

According to the present invention I provide at intervals along the pipe line, short, removable sections, which are placed between adjacent lengths of the piping. These secn tions comprise an outer shell of steel or iron and an inner casting of Zinc or other material which is electro-positive to the piping. This casting is of substantial thickness and is adapted to withstand corrosive action for a considerable period. The outer steel shell afords the necessary tensile strength and serves to protect the soft inner casting of Zinc against impact and'abrasion. The sections are readily removable, and can be replaced at relatively small cost when the zinc has finally corroded away.

The invention will be more clearly understood by reference to the accompanying drawings, in which Fig. 1 a longitudinal sectional view showing a portion of a pipe line, provided with a removable section having an internal zinc casting.

Figs. 2, 3 and 4 are views similar to Fig. 1 showing modifications of the removable section.

Fig. 5 is a sectional view showing a detail of F ig. 4.

Referring first to Fig. 1, reference numerals 10, 11 denote portions of adjacent lengths of an ordinary pipe line, each being provided with a collar 12 of ordinary construction. For the purpose of protecting the interior of the pipe line against corrosion an intermediate composite section is provided having an outer steel shell 14 and an interior casting 13 of zinc. As shown, one end 15 of the steel shell is swaged to form a nipple which lits into one ot the collars 12 of the pipe line.

The other end of the section is connected to the pipe line 11 through a short intermediate steel section having a nipple 16 adapted to fit the collar 12, and an upset end 17 which abuts the composite Zinc and steel section, and is connected thereto by means of a. suitable collar 18.

Fig. 2 shows a construction similar to Fig. 1 except that the upset steel sect-ion is eliminated, both ends of the composite Zinc and steel sections being swaged to form nipples adapted to tit the collars 12. The device as illustrated in Fig. 2 may, if desired, be formed of two swaged nipples, into which the protecting material has been cast. The two enlarged ends of the nipples are threaded and joined together by a screw Collar.

In Fig. 3 the connecting steel section is used, but in this case the end of the upset portion is hollowed out and internally threaded as at 19, thus eliminating` the collar 18 shown in Fig. 1.

According to the construction shown in Figs. 4 and 5, the composite zinc and steel section is in the form of a hollow cylinder composed of an internal zinc casting or ring 20, and an outer steel shell 21, the latter being threaded at its ends to t collars 18 by means of which it may be removably attached to short steel sections 22 at each end thereof.

If desired, other means of removably connecting the composite zinc and steel section to the pipe line may be employed, those embodiments described above, however, being preferred.

It Will be noted that in each instance the internal diameter of the Zinc casting or ring,` is the same as that of the pipe line, so that the flow is in no Way interferred with. The presence of the zinc or other metal which is electro-positive with respect to themetal of Which the piping is composed, serves to prevent corrosion of the interior of the entire pipe line, the Zinc being attacked in preference to the piping. As a ring of zinc of substantial thickness is provided, the protection afforded will last for a considerable period of time. When, however, the zinc inally becomes corroded and is no longer eHective, the composite zinc and steel section may be readily replaced at a relatively small cost.

What I claim is A device for protecting the interior of iron and steel pipes against corrosion, comprising a removable coupling` section located intermediate adjacent lengths of pipe, and consisting of an outer steel shell, and an interior casting of zinc of substantial thickness, the outer steel shell being of substantially the same thickness as the adjacent piping, the internal diameter of the coupling,Y being substantially the same as that of the pipe, and the exterior diameter ol the coupling being` substantially greater than the exterior' diameter of the pipe.

In testimony whereof I affix my signature.

RONALD VAN AUKEN MILLS. 

